/*******************************************************************************
* Copyright (c) 2014, 2015 IBM Corp.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v1.0 which accompany this distribution.
*
* The Eclipse Public License is available at
*    http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
*   http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
*    Ian Craggs - initial API and implementation and/or initial documentation
*    Ian Craggs - fix for bug 458512 - QoS 2 messages
*    Ian Craggs - fix for bug 460389 - send loop uses wrong length
*    Ian Craggs - fix for bug 464169 - clearing subscriptions
*    Ian Craggs - fix for bug 464551 - enums and ints can be different size
*    Mark Sonnentag - fix for bug 475204 - inefficient instantiation of Timer
*    Ian Craggs - fix for bug 475749 - packetid modified twice
*******************************************************************************/

#if !defined(MQTTCLIENT_H)
#define MQTTCLIENT_H

#include <string.h>
#include "FP.h"
#include "MQTTPacket.h"
#include "stdio.h"
#include "MQTTLogging.h"

#if !defined(MQTTCLIENT_QOS1)
#define MQTTCLIENT_QOS1 1
#endif
#if !defined(MQTTCLIENT_QOS2)
#define MQTTCLIENT_QOS2 1
#endif

//#define MQTT_DEBUG 1

namespace MQTT
{


    enum QoS { QOS0, QOS1, QOS2 };

    // all failure return codes must be negative
    enum returnCode { BUFFER_OVERFLOW = -2, FAILURE = -1, SUCCESS = 0 };


    struct Message
    {
        enum QoS qos;
        bool retained;
        bool dup;
        unsigned short id;
        void *payload;
        size_t payloadlen;
    };


    struct MessageData
    {
        MessageData(MQTTString &aTopicName, struct Message &aMessage)  : message(aMessage), topicName(aTopicName)
        {
        }

        struct Message &message;
        MQTTString &topicName;
    };


    class PacketId
    {
    public:
        PacketId()
        {
            next = 0;
        }

        int        getNext()
        {
            return next = (next == MAX_PACKET_ID) ? 1 : next + 1;
        }

    private:
        static const int        MAX_PACKET_ID = 65535;
        int                     next;
    };


    /**
     * @class Client
     * @brief blocking, non-threaded MQTT client API
     *
     * This version of the API blocks on all method calls, until they are complete.  This means that only one
     * MQTT request can be in process at any one time.
     * @param Network a network class which supports send, receive
     * @param Timer a timer class with the methods:
     */
    template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE = 100, int MAX_MESSAGE_HANDLERS = 5>
    class Client
    {

    public:

        typedef void (*messageHandler)(MessageData &);

        /** Construct the client
         *  @param network - pointer to an instance of the Network class - must be connected to the endpoint
         *      before calling MQTT connect
         *  @param limits an instance of the Limit class - to alter limits as required
         */
        Client(Network &network, unsigned int command_timeout_ms = 30000);

        /** Set the default message handling callback - used for any message which does not match a subscription message handler
         *  @param mh - pointer to the callback function
         */
        void        setDefaultMessageHandler(messageHandler mh)
        {
            defaultMessageHandler.attach(mh);
        }

        /** MQTT Connect - send an MQTT connect packet down the network and wait for a Connack
         *  The nework object must be connected to the network endpoint before calling this
         *  Default connect options are used
         *  @return success code -
         */
        int        connect();

        /** MQTT Connect - send an MQTT connect packet down the network and wait for a Connack
         *  The nework object must be connected to the network endpoint before calling this
         *  @param options - connect options
         *  @return success code -
         */
        int        connect(MQTTPacket_connectData &options);

        /** MQTT Publish - send an MQTT publish packet and wait for all acks to complete for all QoSs
         *  @param topic - the topic to publish to
         *  @param message - the message to send
         *  @return success code -
         */
        int        publish(const char *topicName, Message &message);

        /** MQTT Publish - send an MQTT publish packet and wait for all acks to complete for all QoSs
         *  @param topic - the topic to publish to
         *  @param payload - the data to send
         *  @param payloadlen - the length of the data
         *  @param qos - the QoS to send the publish at
         *  @param retained - whether the message should be retained
         *  @return success code -
         */
        int        publish(const char *topicName, void *payload, size_t payloadlen, enum QoS qos = QOS0, bool retained = false);

        /** MQTT Publish - send an MQTT publish packet and wait for all acks to complete for all QoSs
         *  @param topic - the topic to publish to
         *  @param payload - the data to send
         *  @param payloadlen - the length of the data
         *  @param id - the packet id used - returned
         *  @param qos - the QoS to send the publish at
         *  @param retained - whether the message should be retained
         *  @return success code -
         */
        int        publish(const char *topicName, void *payload, size_t payloadlen, unsigned short &id, enum QoS qos = QOS1, bool retained = false);

        /** MQTT Subscribe - send an MQTT subscribe packet and wait for the suback
         *  @param topicFilter - a topic pattern which can include wildcards
         *  @param qos - the MQTT QoS to subscribe at
         *  @param mh - the callback function to be invoked when a message is received for this subscription
         *  @return success code -
         */
        int        subscribe(const char *topicFilter, enum QoS qos, messageHandler mh);

        /** MQTT Unsubscribe - send an MQTT unsubscribe packet and wait for the unsuback
         *  @param topicFilter - a topic pattern which can include wildcards
         *  @return success code -
         */
        int        unsubscribe(const char *topicFilter);

        /** MQTT Disconnect - send an MQTT disconnect packet, and clean up any state
         *  @return success code -
         */
        int        disconnect();

        /** A call to this API must be made within the keepAlive interval to keep the MQTT connection alive
         *  yield can be called if no other MQTT operation is needed.  This will also allow messages to be
         *  received.
         *  @param timeout_ms the time to wait, in milliseconds
         *  @return success code - on failure, this means the client has disconnected
         */
        int        yield(unsigned long timeout_ms = 1000L);

        /** Is the client connected?
         *  @return flag - is the client connected or not?
         */
        bool        isConnected()
        {
            return isconnected;
        }

    private:

        void                    cleanSession();
        int                     cycle(Timer &timer);
        int                     waitfor(int packet_type, Timer &timer);
        int                     keepalive();
        int                     publish(int len, Timer &timer, enum QoS qos);

        int                     decodePacket(int *value, int timeout);
        int                     readPacket(Timer &timer);
        int                     sendPacket(int length, Timer &timer);
        int                     deliverMessage(MQTTString &topicName, Message &message);
        bool                    isTopicMatched(char *topicFilter, MQTTString &topicName);

        Network                &ipstack;
        unsigned long           command_timeout_ms;

        unsigned char           sendbuf[MAX_MQTT_PACKET_SIZE];
        unsigned char           readbuf[MAX_MQTT_PACKET_SIZE];

        Timer                   last_sent, last_received;
        unsigned int            keepAliveInterval;
        bool                    ping_outstanding;
        bool                    cleansession;

        PacketId                packetid;

        struct MessageHandlers
        {
            const char *topicFilter;
            FP<void, MessageData &> fp;
        } messageHandlers[MAX_MESSAGE_HANDLERS];      // Message handlers are indexed by subscription topic

        FP<void, MessageData &>          defaultMessageHandler;

        bool                            isconnected;

#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
        unsigned char           pubbuf[MAX_MQTT_PACKET_SIZE]; // store the last publish for sending on reconnect
        int                     inflightLen;
        unsigned short          inflightMsgid;
        enum QoS                inflightQoS;
#endif

#if MQTTCLIENT_QOS2
        bool        pubrel;
#if !defined(MAX_INCOMING_QOS2_MESSAGES)
#define MAX_INCOMING_QOS2_MESSAGES 10
#endif
        unsigned short          incomingQoS2messages[MAX_INCOMING_QOS2_MESSAGES];
        bool                    isQoS2msgidFree(unsigned short id);
        bool                    useQoS2msgid(unsigned short id);
        void                    freeQoS2msgid(unsigned short id);
#endif

    };

}


template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS>
void MQTT::Client<Network, Timer, a, MAX_MESSAGE_HANDLERS>::        cleanSession()
{
    ping_outstanding = false;
    for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
        messageHandlers[i].topicFilter = 0;
    isconnected = false;

#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
    inflightMsgid = 0;
    inflightQoS = QOS0;
#endif

#if MQTTCLIENT_QOS2
    pubrel = false;
    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
        incomingQoS2messages[i] = 0;
#endif
}


template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS>
MQTT::Client<Network, Timer, a, MAX_MESSAGE_HANDLERS>::Client(Network &network, unsigned int command_timeout_ms)  : ipstack(network), packetid()
{
    this->command_timeout_ms = command_timeout_ms;
    cleanSession();
}


#if MQTTCLIENT_QOS2
template<class Network, class Timer, int a, int b>
bool MQTT::Client<Network, Timer, a, b>::        isQoS2msgidFree(unsigned short id)
{
    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
    {
        if (incomingQoS2messages[i] == id)
            return false;
    }
    return true;
}


template<class Network, class Timer, int a, int b>
bool MQTT::Client<Network, Timer, a, b>::        useQoS2msgid(unsigned short id)
{
    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
    {
        if (incomingQoS2messages[i] == 0)
        {
            incomingQoS2messages[i] = id;
            return true;
        }
    }
    return false;
}


template<class Network, class Timer, int a, int b>
void MQTT::Client<Network, Timer, a, b>::        freeQoS2msgid(unsigned short id)
{
    for (int i = 0; i < MAX_INCOMING_QOS2_MESSAGES; ++i)
    {
        if (incomingQoS2messages[i] == id)
        {
            incomingQoS2messages[i] = 0;
            return;
        }
    }
}
#endif


template<class Network, class Timer, int a, int b>
int MQTT::Client<Network, Timer, a, b>::        sendPacket(int length, Timer &timer)
{
    int        rc = FAILURE,
               sent = 0;

    while (sent < length && !timer.expired())
    {
        rc = ipstack.write(&sendbuf[sent], length - sent, timer.left_ms());
        if (rc < 0)  // there was an error writing the data
            break;
        sent += rc;
    }
    if (sent == length)
    {
        if (this->keepAliveInterval > 0)
            last_sent.countdown(this->keepAliveInterval);  // record the fact that we have successfully sent the packet
        rc = SUCCESS;
    }
    else
        rc = FAILURE;

#if defined(MQTT_DEBUG)
    char        printbuf[150];
    DEBUG("Rc %d from sending packet %s\n", rc, MQTTFormat_toServerString(printbuf, sizeof(printbuf), sendbuf, length));
#endif
    return rc;
}


template<class Network, class Timer, int a, int b>
int MQTT::Client<Network, Timer, a, b>::        decodePacket(int *value, int timeout)
{
    unsigned char           c;
    int                     multiplier = 1;
    int                     len = 0;
    const int               MAX_NO_OF_REMAINING_LENGTH_BYTES = 4;

    *value = 0;
    do
    {
        int        rc = MQTTPACKET_READ_ERROR;

        if (++len > MAX_NO_OF_REMAINING_LENGTH_BYTES)
        {
            rc = MQTTPACKET_READ_ERROR; /* bad data */
            goto exit;
        }
        rc = ipstack.read(&c, 1, timeout);
        if (rc != 1)
            goto exit;
        *value += (c & 127) * multiplier;
        multiplier *= 128;
    }
    while ((c & 128) != 0);
exit:
    return len;
}


/**
 * If any read fails in this method, then we should disconnect from the network, as on reconnect
 * the packets can be retried.
 * @param timeout the max time to wait for the packet read to complete, in milliseconds
 * @return the MQTT packet type, or -1 if none
 */
template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        readPacket(Timer &timer)
{
    int                 rc = FAILURE;
    MQTTHeader          header = {0};
    int                 len = 0;
    int                 rem_len = 0;

    /* 1. read the header byte.  This has the packet type in it */
    if (ipstack.read(readbuf, 1, timer.left_ms()) != 1)
        goto exit;

    len = 1;
    /* 2. read the remaining length.  This is variable in itself */
    decodePacket(&rem_len, timer.left_ms());
    len += MQTTPacket_encode(readbuf + 1, rem_len); /* put the original remaining length into the buffer */

    if (rem_len > (MAX_MQTT_PACKET_SIZE - len))
    {
        rc = BUFFER_OVERFLOW;
        goto exit;
    }

    /* 3. read the rest of the buffer using a callback to supply the rest of the data */
    if (rem_len > 0 && (ipstack.read(readbuf + len, rem_len, timer.left_ms()) != rem_len))
        goto exit;

    header.byte = readbuf[0];
    rc = header.bits.type;
    if (this->keepAliveInterval > 0)
        last_received.countdown(this->keepAliveInterval);  // record the fact that we have successfully received a packet
exit:

#if defined(MQTT_DEBUG)
    if (rc >= 0)
    {
        char        printbuf[50];
        DEBUG("Rc %d from receiving packet %s\n", rc, MQTTFormat_toClientString(printbuf, sizeof(printbuf), readbuf, len));
    }
#endif
    return rc;
}


// assume topic filter and name is in correct format
// # can only be at end
// + and # can only be next to separator
template<class Network, class Timer, int a, int b>
bool MQTT::Client<Network, Timer, a, b>::        isTopicMatched(char *topicFilter, MQTTString &topicName)
{
    char       *curf = topicFilter;
    char       *curn = topicName.lenstring.data;
    char       *curn_end = curn + topicName.lenstring.len;

    while (*curf && curn < curn_end)
    {
        if (*curn == '/' && *curf != '/')
            break;
        if (*curf != '+' && *curf != '#' && *curf != *curn)
            break;
        if (*curf == '+')
        {
            // skip until we meet the next separator, or end of string
            char       *nextpos = curn + 1;
            while (nextpos < curn_end && *nextpos != '/')
                nextpos = ++curn + 1;
        }
        else if (*curf == '#')
            curn = curn_end - 1;    // skip until end of string
        curf++;
        curn++;
    };

    return (curn == curn_end) && (*curf == '\0');
}



template<class Network, class Timer, int a, int MAX_MESSAGE_HANDLERS>
int MQTT::Client<Network, Timer, a, MAX_MESSAGE_HANDLERS>::        deliverMessage(MQTTString &topicName, Message &message)
{
    int        rc = FAILURE;

    // we have to find the right message handler - indexed by topic
    for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
    {
        if (messageHandlers[i].topicFilter != 0 && (MQTTPacket_equals(&topicName, (char *)messageHandlers[i].topicFilter) ||
                isTopicMatched((char *)messageHandlers[i].topicFilter, topicName)))
        {
            if (messageHandlers[i].fp.attached())
            {
                MessageData        md(topicName, message);
                messageHandlers[i].fp(md);
                rc = SUCCESS;
            }
        }
    }

    if (rc == FAILURE && defaultMessageHandler.attached())
    {
        MessageData        md(topicName, message);
        defaultMessageHandler(md);
        rc = SUCCESS;
    }

    return rc;
}



template<class Network, class Timer, int a, int b>
int MQTT::Client<Network, Timer, a, b>::        yield(unsigned long timeout_ms)
{
    int             rc = SUCCESS;
    Timer           timer;

    timer.countdown_ms(timeout_ms);
    while (!timer.expired())
    {
        if (cycle(timer) < 0)
        {
            rc = FAILURE;
            break;
        }
    }

    return rc;
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        cycle(Timer &timer)
{
    /* get one piece of work off the wire and one pass through */

    // read the socket, see what work is due
    int         packet_type = readPacket(timer);

    int         len = 0,
                rc = SUCCESS;

    switch (packet_type)
    {
    case FAILURE:
    case BUFFER_OVERFLOW:
        rc = packet_type;
        break;
    case CONNACK:
    case PUBACK:
    case SUBACK:
        break;
    case PUBLISH:
    {
        MQTTString          topicName = MQTTString_initializer;
        Message             msg;
        int                 intQoS;
        if (MQTTDeserialize_publish((unsigned char *)&msg.dup, &intQoS, (unsigned char *)&msg.retained, (unsigned short *)&msg.id, &topicName,
                                    (unsigned char **)&msg.payload, (int *)&msg.payloadlen, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
            goto exit;
        msg.qos = (enum QoS)intQoS;
#if MQTTCLIENT_QOS2
        if (msg.qos != QOS2)
#endif
            deliverMessage(topicName, msg);
#if MQTTCLIENT_QOS2
        else if (isQoS2msgidFree(msg.id))
        {
            if (useQoS2msgid(msg.id))
                deliverMessage(topicName, msg);
            else
                WARN("Maximum number of incoming QoS2 messages exceeded");
        }
#endif
#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
        if (msg.qos != QOS0)
        {
            if (msg.qos == QOS1)
                len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, PUBACK, 0, msg.id);
            else if (msg.qos == QOS2)
                len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, PUBREC, 0, msg.id);
            if (len <= 0)
                rc = FAILURE;
            else
                rc = sendPacket(len, timer);
            if (rc == FAILURE)
                goto exit;     // there was a problem
        }
        break;
#endif
    }
#if MQTTCLIENT_QOS2
    case PUBREC:
    case PUBREL:
        unsigned short mypacketid;
        unsigned char        dup, type;
        if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
            rc = FAILURE;
        else if ((len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE,
                                          (packet_type == PUBREC) ? PUBREL : PUBCOMP, 0, mypacketid)) <= 0)
            rc = FAILURE;
        else if ((rc = sendPacket(len, timer)) != SUCCESS)     // send the PUBREL packet
            rc = FAILURE;     // there was a problem
        if (rc == FAILURE)
            goto exit;     // there was a problem
        if (packet_type == PUBREL)
            freeQoS2msgid(mypacketid);
        break;

    case PUBCOMP:
        break;
#endif
    case PINGRESP:
        ping_outstanding = false;
        break;
    }
    keepalive();
exit:
    if (rc == SUCCESS)
        rc = packet_type;
    return rc;
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        keepalive()
{
    int        rc = FAILURE;

    if (keepAliveInterval == 0)
    {
        rc = SUCCESS;
        goto exit;
    }

    if (last_sent.expired() || last_received.expired())
    {
        if (!ping_outstanding)
        {
            Timer           timer(1000);
            int             len = MQTTSerialize_pingreq(sendbuf, MAX_MQTT_PACKET_SIZE);
            if (len > 0 && (rc = sendPacket(len, timer)) == SUCCESS) // send the ping packet
                ping_outstanding = true;
        }
    }

exit:
    return rc;
}


// only used in single-threaded mode where one command at a time is in process
template<class Network, class Timer, int a, int b>
int MQTT::Client<Network, Timer, a, b>::        waitfor(int packet_type, Timer &timer)
{
    int        rc = FAILURE;

    do
    {
        if (timer.expired())
            break;  // we timed out
    }
    while ((rc = cycle(timer)) != packet_type);

    return rc;
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        connect(MQTTPacket_connectData &options)
{
    Timer           connect_timer(command_timeout_ms);
    int             rc = FAILURE;
    int             len = 0;

    if (isconnected) // don't send connect packet again if we are already connected
        goto exit;

    this->keepAliveInterval = options.keepAliveInterval;
    this->cleansession = options.cleansession;
    if ((len = MQTTSerialize_connect(sendbuf, MAX_MQTT_PACKET_SIZE, &options)) <= 0)
        goto exit;
    if ((rc = sendPacket(len, connect_timer)) != SUCCESS)  // send the connect packet
        goto exit;  // there was a problem

    if (this->keepAliveInterval > 0)
        last_received.countdown(this->keepAliveInterval);
    // this will be a blocking call, wait for the connack
    if (waitfor(CONNACK, connect_timer) == CONNACK)
    {
        unsigned char           connack_rc = 255;
        bool                    sessionPresent = false;
        if (MQTTDeserialize_connack((unsigned char *)&sessionPresent, &connack_rc, readbuf, MAX_MQTT_PACKET_SIZE) == 1)
            rc = connack_rc;
        else
            rc = FAILURE;
    }
    else
        rc = FAILURE;

#if MQTTCLIENT_QOS2
    // resend any inflight publish
    if (inflightMsgid > 0 && inflightQoS == QOS2 && pubrel)
    {
        if ((len = MQTTSerialize_ack(sendbuf, MAX_MQTT_PACKET_SIZE, PUBREL, 0, inflightMsgid)) <= 0)
            rc = FAILURE;
        else
            rc = publish(len, connect_timer, inflightQoS);
    }
    else
#endif
#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
        if (inflightMsgid > 0)
        {
            memcpy(sendbuf, pubbuf, MAX_MQTT_PACKET_SIZE);
            rc = publish(inflightLen, connect_timer, inflightQoS);
        }
#endif

exit:
    if (rc == SUCCESS)
        isconnected = true;
    return rc;
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        connect()
{
    MQTTPacket_connectData        default_options = MQTTPacket_connectData_initializer;
    return connect(default_options);
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int MAX_MESSAGE_HANDLERS>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, MAX_MESSAGE_HANDLERS>::        subscribe(const char *topicFilter, enum QoS qos, messageHandler messageHandler)
{
    int                 rc = FAILURE;
    Timer               timer(command_timeout_ms);
    int                 len = 0;
    MQTTString          topic = {(char *)topicFilter, {0, 0}};

    if (!isconnected)
        goto exit;

    len = MQTTSerialize_subscribe(sendbuf, MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic, (int *)&qos);
    if (len <= 0)
        goto exit;
    if ((rc = sendPacket(len, timer)) != SUCCESS) // send the subscribe packet
        goto exit;             // there was a problem

    if (waitfor(SUBACK, timer) == SUBACK)      // wait for suback
    {
        int                     count = 0, grantedQoS = -1;
        unsigned short          mypacketid;
        if (MQTTDeserialize_suback(&mypacketid, 1, &count, &grantedQoS, readbuf, MAX_MQTT_PACKET_SIZE) == 1)
            rc = grantedQoS;  // 0, 1, 2 or 0x80
        if (rc != 0x80)
        {
            for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
            {
                if (messageHandlers[i].topicFilter == 0)
                {
                    messageHandlers[i].topicFilter = topicFilter;
                    messageHandlers[i].fp.attach(messageHandler);
                    rc = 0;
                    break;
                }
            }
        }
    }
    else
        rc = FAILURE;

exit:
    if (rc != SUCCESS)
        cleanSession();
    return rc;
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int MAX_MESSAGE_HANDLERS>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, MAX_MESSAGE_HANDLERS>::        unsubscribe(const char *topicFilter)
{
    int                 rc = FAILURE;
    Timer               timer(command_timeout_ms);
    MQTTString          topic = {(char *)topicFilter, {0, 0}};
    int                 len = 0;

    if (!isconnected)
        goto exit;

    if ((len = MQTTSerialize_unsubscribe(sendbuf, MAX_MQTT_PACKET_SIZE, 0, packetid.getNext(), 1, &topic)) <= 0)
        goto exit;
    if ((rc = sendPacket(len, timer)) != SUCCESS) // send the unsubscribe packet
        goto exit;  // there was a problem

    if (waitfor(UNSUBACK, timer) == UNSUBACK)
    {
        unsigned short        mypacketid; // should be the same as the packetid above
        if (MQTTDeserialize_unsuback(&mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) == 1)
        {
            rc = 0;

            // remove the subscription message handler associated with this topic, if there is one
            for (int i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
            {
                if (messageHandlers[i].topicFilter != 0 && strcmp(messageHandlers[i].topicFilter, topicFilter) == 0)
                {
                    messageHandlers[i].topicFilter = 0;
                    break;
                }
            }
        }
    }
    else
        rc = FAILURE;

exit:
    if (rc != SUCCESS)
        cleanSession();
    return rc;
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        publish(int len, Timer &timer, enum QoS qos)
{
    int        rc;

    if ((rc = sendPacket(len, timer)) != SUCCESS) // send the publish packet
        goto exit;  // there was a problem

#if MQTTCLIENT_QOS1
    if (qos == QOS1)
    {
        if (waitfor(PUBACK, timer) == PUBACK)
        {
            unsigned short          mypacketid;
            unsigned char           dup, type;
            if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
                rc = FAILURE;
            else if (inflightMsgid == mypacketid)
                inflightMsgid = 0;
        }
        else
            rc = FAILURE;
    }
#elif MQTTCLIENT_QOS2
    else if (qos == QOS2)
    {
        if (waitfor(PUBCOMP, timer) == PUBCOMP)
        {
            unsigned short          mypacketid;
            unsigned char           dup, type;
            if (MQTTDeserialize_ack(&type, &dup, &mypacketid, readbuf, MAX_MQTT_PACKET_SIZE) != 1)
                rc = FAILURE;
            else if (inflightMsgid == mypacketid)
                inflightMsgid = 0;
        }
        else
            rc = FAILURE;
    }
#endif

exit:
    if (rc != SUCCESS)
        cleanSession();
    return rc;
}



template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        publish(const char *topicName, void *payload, size_t payloadlen, unsigned short &id, enum QoS qos, bool retained)
{
    int                 rc = FAILURE;
    Timer               timer(command_timeout_ms);
    MQTTString          topicString = MQTTString_initializer;
    int                 len = 0;

    if (!isconnected)
        goto exit;

    topicString.cstring = (char *)topicName;

#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
    if (qos == QOS1 || qos == QOS2)
        id = packetid.getNext();
#endif

    len = MQTTSerialize_publish(sendbuf, MAX_MQTT_PACKET_SIZE, 0, qos, retained, id,
                                topicString, (unsigned char *)payload, payloadlen);
    if (len <= 0)
        goto exit;

#if MQTTCLIENT_QOS1 || MQTTCLIENT_QOS2
    if (!cleansession)
    {
        memcpy(pubbuf, sendbuf, len);
        inflightMsgid = id;
        inflightLen = len;
        inflightQoS = qos;
#if MQTTCLIENT_QOS2
        pubrel = false;
#endif
    }
#endif

    rc = publish(len, timer, qos);
exit:
    return rc;
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        publish(const char *topicName, void *payload, size_t payloadlen, enum QoS qos, bool retained)
{
    unsigned short        id = 0; // dummy - not used for anything
    return publish(topicName, payload, payloadlen, id, qos, retained);
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        publish(const char *topicName, Message &message)
{
    return publish(topicName, message.payload, message.payloadlen, message.qos, message.retained);
}


template<class Network, class Timer, int MAX_MQTT_PACKET_SIZE, int b>
int MQTT::Client<Network, Timer, MAX_MQTT_PACKET_SIZE, b>::        disconnect()
{
    int             rc = FAILURE;
    Timer           timer(command_timeout_ms); // we might wait for incomplete incoming publishes to complete
    int             len = MQTTSerialize_disconnect(sendbuf, MAX_MQTT_PACKET_SIZE);
    if (len > 0)
        rc = sendPacket(len, timer);            // send the disconnect packet

    if (cleansession)
        cleanSession();
    else
        isconnected = false;
    return rc;
}


#endif
